Most digital editing programs include a mode “preview” to visualize, about, The result of applying a filter an image.
Blender has a tool in the node editor which allows to compare two images in one window.
The proximity of the images allows better appreciate the differences between the two, which facilitates the approximation to the desired result, interactively, with the controls of the filters.
Incorporate new viewers
Blender admite Viewers “simple” that only let you see a picture, The display “double” for simultaneous two images in the same window.
To embed a simple viewer in the context menu select the option toolbar “Viewer” between output devices:
- two input images (yellow circles)
- controls associated with each display form, along with a small window that shows both images.
Being a small control, the image will be scaled, so it is not possible for us to observe in detail the contrast that we make between the two images used as input to the control.
We can improve the result display
We will activate button BackDrop to provide a detailed display in the node editor window.
Before obtaining images in the node editor window, or viewfinder, we complete the connectivity of the graph.
For example if you are modifying an input image by a smoothing filter (Soften), and sending the result to an output file, we have the following graph:
We can link the original image and the viewer modified our “double”
The result would look like this:
Node “SplitViewer” can decide whether the window is split horizontally or vertically, and how much of the window (%) used for the original image and how much for the final.
If you have multiple viewers in a more complex example, simply selecting the viewer that we have active, will update the background image (Backdrop).
Combine filters and add? Intermediate viewers?